Wet spinning apparatus



Jam. 24, 1956 w. H. BRADSHAW 2,731,667

WET SPINNING APPARATUS Filed May 16, 1951 2 Sheec-Sheet 1 INVENTOR. iWILLIAM H. BRADSHAW ATTORNEYS.

Jan. 24, 1956 Filed May 16. 1951 W. H. BRADSHAW WET SPINNING APPARATUS'2 Sheets-Shet 2 INVENTOR. WILLIAM H. BRADSHAW ATTORNEYS.

United States Patent WET SPINNING APPARATUS William H. Bradshaw, NewRochelle, N. Y., assignor to Celanese Corporation of America, New York,N. Y., a corporation of Delaware Application May 16, 1951, Serial No.226,593

Claims. (Cl. 18-8) This invention relates to the production of viscoserayon filamentary materials and relates more particularly to a novelprocess and apparatus for the production of viscose rayon filamentarymaterials in a continuous manner.

An important object of this invention is to provide a novel process andapparatus for the production of viscose rayon filamentary materials in acontinuous manner which will be especially efiicient in operation andsimple in construction.

Other objects of this invention, together with certain details or"construction and combinations of parts, will be apparent from thefollowing detailed description and claims.

In the production of viscose rayon filamentary materials, particularlyviscose rayon fibers of staple length, it is necessary to subject saidfilamentary materials to a series of successive treatments under closelycontrolled conditions to obtain products having desirable physicalproperties. Advantageously, to minimize the expense involved inproducing the viscose rayon filamentary materials, the successivetreatments should be carried out automatically and with a minimum ofmanual labor.

According to the present invention, there is provided a novel processand apparatus for the production of viscose rayon filamentary materialswhich will fulfill the foregoing requirements, the apparatus beingdivided into four sections: a spinning section, a stretching section, acooling section, and a cutting and opening section, through whichsections the viscose rayon filamentary materials pass in succession. Thepresent application relates specifically to the spinning section of theapparatus. In the spinning section, a viscose composition is pumpedthrough a spinning jet, in the form of a strand containing up to 5000,or more, filaments into a coagulating medium which initiates the settingof the filaments. The strand and the coagulating medium are then causedto flow inthe same direction through a generally U-shaped spinning tubewherein the setting of the filaments continues. As the strand emergesfrom the spinning tube, it is combined with the strands from one or morejets into a tow and is passed around a godet wheel which determines thespeed of the tow and also provides a resistance against which the towcan be stretched by a drum over which it passes later on.

"The term filamentary materials is employed herein to' include filamentsof indefinite length as well as fibers of staple length.

A preferred embodiment of the apparatus of this invention is shown inthe accompanying drawings wherein:

Fig. 1 is a cross-sectional view of the apparatus, taken on an enlargedscale along the line 11 in Fig. 2, inthe direction of the arrows,

Big. 2 is a front elevational view, with portions broken away, of theapparatus,

Fig. 3 is a cross-sectional view, taken along the line 3-3 in Fig. 1, inthe direction of the arrows, and

Fig. 4 is a detail perspective view, on an enlarged scale 2,731 ,fibiPatented Jan. 24, 1956 and with parts broken away, of the inlet tunnelfor guiding the tow into the spinning tube.

Spinning section Referring now to the drawings, and more particularly toFigs. 1 and 2 thereof, the reference numeral 21 designates conduitsthrough which a suitably ripened viscose composition is pumped by anysuitable means (not shown) through a goose-neck, indicated generally byreference numeral 22, to a spinning jet, indicated generally byreference numeral 23. The spinning jet 23 is positioned in a trough 24into which a stream of a suitable coagulating medium is pumpedcontinuously through a conduit 25. The viscose composition emerges fromthe spinning jet 23 into the coagulating medium in the form of a strand26 containing up to about'5000, or more, individual filaments which arecaused to set by the action thereon of the coagulating medium. Thestrand 26 together with the coagulating medium then pass throughsuitable guide means, such as an inlet funnel 27, into a generally U-shaped spinning tube 28, composed of a vertically disposed conduit 29, ahorizontally disposed connecting conduit 31 and avertically disposedconduit 32, all joined together with elbows 33. Grooved guides 34 areprovided in each of the elbows 33 to direct the strand 26 through thetube 28 and are positioned so as to guide the strand 26 along the centerlines of the conduits 29, 31 and 32 thereby minimizing the developmentof turbulence in said conduits; The shape and positioning of the groovedguides 34 also tend to cause the fiow of the coagulating medium to holdthe strand 26 away from the guide thus reducing greatly the tensiondeveloped by the friction of the strand 26 against the said guide.

A constant .head of coagulating medium is maintained on the inlet funnel27 by pumping an excess of said medium into the trough 24 and permittingsaid excess to overflow into a channel 35 connected to a trough 36 whichextends parallel to and is positioned adjacent the trough 24. The strand26 and the coagulating medium emerge from-the spinning tube 28 into thetrough 36 through suitable guide means, such as an outlet funnel 37,whose cross-sectional area increases toward the discharge end thereofwhereby the velocity of the coagulating medium will decrease immediatelyprior to its discharge from said outlet funnel. As a result, thecoagulating medium will show little or no tendency to spurt from saidoutlet funnel as a column enclosing the tow 26, although a certainamount of the coagulating medium will, of course, be held within theinterstices between'the filaments of said strand. The coagulating mediumwhich overflows .into the channel 35 and which flows through the outletfunnel 37 is drained from the trough 36 through a discharge conduit 38which is made sufficiently large to prevent the accumulation of largequantities of liquid in said trough. A screen 39 spaced slightly abovethe fioor of the trough 36 traps any broken fibers that may be formedduring the spinning operation and keeps them from flowing into thedischarge conduit 38. The screen 39also holds back thestrand 26 whichemerges from the outlet funnel 37 when starting up the apparatus,permitting the operator to string up the said strand without having toremove any of the strand from the trough 36 during the start up period.The trough 36 is provided with a removable cover 41 and is connected toan exhaust conduit 42 through which any gases or fumes that are.liberated during the spinning operation may be drawn oli.

As is shown more clearly in Fig. 4, the inlet funnel 27 is provided withradially extending wings 43 and is seated slidably in a collar 44extending upwardly through the floor ofthe trough 24. One of the wings43 is provided with a groove 45 in thejface thereof which groove isadapted to receive a pin 46 projecting from the collar 44.

When .the pin 46 is contained within the groove 45, the inlet funnel 27is held in elevated position at a point spaced only slightly below thespinning jet 23. In this position, the flow of the coagulating mediuminto the inlet funnel 27 and through the spinning tube.28will carry thestrand 26 into and through said .tube. .Once-ihestrand 26 has beenthreaded through the tube 28, the inlet funnel 27 may be returned to'itsnormal spinning position, as shownin Fig. 2 of the drawings,-in WhiChiiisspaced further away from the spinning jet 23 than-at the start-ofthespinning operation. This mode of starting the spinning operationeliminatesthe necessity for :wiping the face of the spinning jet '23during the starting period and thereby reduces the amount oflaborinvolved in said start up.

After emerging from the outlet funnel 37, the strand 26 passes over atwo-finger guide46', which "wipes away a portion ofthecoagulating mediumadhering-thereto, and then through 'a slot 47 in the'cover 41 to a-godetwheel, indicatedgenerally by reference numeral 48. The strands 26 fromthree spinning jets 23 are joined on *the 'godet wheel 48 to forma=tow-49 which is led from the godet wheel 48 over a guide pin 51 whichis positioned "at a level higher than said godet Wheel. Any desirednumber of spinning jets 23 and godet wheeis 48 may be includedin'thespinning section of the apparatus, and a'tow'49leaving any oneof'thegodet wheels will "ride over the pins 51 without coming into"contact with any'other of the go'det wheels.

The tensions to which the filaments in the strands 26 are subjected intheir passage from the spinning jet '23 to the godet wheel '48may'becloselycon'trolled, to produce products'having the most desirablephysical properties, by regulating the velocity of the 'viscosecomposition through the said spinning jets, the spacing between thespinning jet 23 and the inlet funnel 27, 'thevelocity'with which thecoagulating medium flows :through the spinning tube 28 which can bealtered by changing the effective liquid head under which said mediumflows through said spinning tube and/or the diameter 'of said spinningtube, andthe speed of the godetwheel 48. The two-finger guide 46' mayalso be adjusted to produce a desirable small additional tension betweenthe said guide and the godet wheel 48. Under normal operatingconditions, the 'filaments travel faster than the coagulating mediumimmediately after emerging from the spinning jet 23, then thecoagulatingmedium travels faster than the filaments as -it flows into and throughthe-first portion of the spinning tube 28, and finally the coagulatingmedium travels at the same rate as or somewhat slower than the filamentsas it flows through the 'last portion of the spinning tube.

In addition topermitting close control of all the condi-' tions underwhich the strand 26 is produced, the spinning section of -the apparatusof this invention provides a long bath travel in a very small spacehorizontally which brings the spinnerette 23 and the godetwheel 48 intosuch close proximity that stringing up by a single operator is'extremelysimple. 'The spinning sectionis also self-threading from the spinnerette23 through the spinning tube 28 and is free from moving guides orrollers so that its construction and maintenance is simplified. Thespinning jets 23 are effectively separated one from the other so thatfresh coagulating medium is brought 'to the filaments emerging from eachof said jets without having been contaminated or-its concentrationchanged by contact with viscose .from any other jet. Moreover, thefilaments from one jet cannot interfere in any way with those of otherjets either during start up or when there is a breakdown.

In producing a strand containing a large number of individual filaments,it'is important to provide anadequate flow of coagulating medium to each.of the filaments as it emerges from the spinning jet .23 to insure that.each of the filaments is treated in the same :manner and that the gasesliberated from the viscose composition are swept away from the vicinityof the spinning jet. If an adequate flow of coagulating medium is notprovided, a sutlicient 7 quantity of the gases liberated from theviscose composi;

tion may accumulate on the lower face of the spinnerette to form bubbleswhich may interrupt the continuity of spinning of one or more filaments,particularly, where as here, the filaments are spun downwardly from thelower face of the spinnerette. Inapplication Serial No. 224,353, filedMay 3, 1951, of Russell 0. Denyes, now U. S. Patent No.2,673,368,-dated.Mar ch 13, .1954, there are disclosed spinnerettes thatare specially adapted to be used in the. apparatus of the presentinvention and 'will insure ;an adequate flow of coagulating medium tothe filaments emerging from each of the apertures in the spinnerette.

Since the solutions employed and produced :during the manufacture of theviscose fibers .are corrosive, the several parts of the apparatusemployed for handling the same are made of or coated with corrosionresistant material such as hard rubber, plastics, ceramics, lead,stainless steel and the like depending upon the use to which each partis put and the mechanical strength requiredthereof.

It is to be understood that the foregoing detailed :de-' scription isgiven merely by way .of illustration and that many variations may bemade therein without departing from "the spirit of my invention.

Having described my invention, what I desireto'secure by Letters Patentis:

1. An apparatus for the production of filamentarymaterials comprising atrough for holding a coagulating medium, a second trough contiguous to.said first trough, a.

channel communicating with said troughs for conducting overflowcoagulating medium from said first trough to said second trough, aspinning jet'positioned in said first trough for extruding afilament-forming composition into said coagulatingmedium in the form offilamentary materials,

and a generally U-shaped spinning tube extending from said first troughto said second trough for carrying the filamentary materials andcoagulating medium from said first trough to said second trough.

2. An apparatus for the production of filamentarymaterials, comprising alongitudinally extending trough .tor holding a coagulating medium,asecond trough contiguous and parallel to said first trough, a channelbetween and communicating with said troughs for conducting overflowcoagulating medium .from said first trough to said second trough, aplurality of spinning jets in :said first trough for extruding afilament-forming composition into said coagulating medium in the form offilamentary materials, .and a plurality of generallyU-shapedspinningatubes extending from said first trough to said seconditrough :for carrying filamentary materialsand coagulating medium fromsaid first trough to said second trough.

3. .An apparatus for the production of filamentary materials, comprisinga trough for holding a coagulating medium, aspinning jet positioned insaid trough for extruding a filament-forming composition into saidcoagulating medium in the form of filamentary materials, a spire ningtube extending away from said trough for carrying the filamentarymaterials and the coagulating medium away from said trough, a movableinlet funnel cooperating with said spinning tube, and means for holdingsaid inlet funnel in raised position so as to reduce .the dis? tancebetween the spinning jet and the inlet funnel at the start of thespinning operation to assist in guiding the filamentary materialsthrough the spinning tube and in reducing the wiping of the spinning jetrequired at the start of the spinning operation.

4. An apparatus'for the production of filamentary materials, comprisingatrough for holding a coagulating medium, a'spinning jet positioned in'said trough for extruding a filament-forming composition into saidcoagulating medium in the form of filamentary materials, a'second'trough, a generally U-shaped spinning tube extending from saidfirst trough to said second trough for carrying the fila' mentarymaterials and the coagulating medium from" the first trough to thesecondtrough, a movable inlet funnelcooperating with said spinning tube, andmeans for holding said inlet tunnel in raised position so as to reducethe distance between the spinning jet and the inlet funnel at the startof the spinning operation to assist in guiding the filamentary materialsthrough the spinning tube and in reducing the wiping of the spinning jetrequired at the start of the spinning operation.

5. An apparatus for the production of filamentary materials, comprisinga trough for holding a coagulating medium, a spinning jet facingdownwardly positioned in said trough for extruding a filament-formingcomposition vertically downward into said coagulating medium in the formof filamentary materials, a second trough positioned adjacent to saidfirst trough, a generally U-shaped spinning tube having its legspositioned vertically upward and having one leg positioned beneath saidspinning jet, said tube extending from said first trough to said secondtrough for carrying the filamentary materials and the coagulating mediumfrom said first trough to said second trough, an inlet funnel forguiding the filamentary materials and the coagulating medium into theleg of the spinning tube positioned beneath said spinning jet, saidinlet tunnel being moveable to reduce the distance between the spinningjet and the entrance to said inlet funnel at the start of the spinningoperation to assist in guiding the filamentary materials through thespinning tube and in reducing the Wiping of the spinning jet required atthe start of the spinning operation, guides positioned in the spinningtube for guiding the filamentary materials along the center line of thespinning tube to minimize .the development of turbulence in the spinningtube, a discharge funnel for guiding the fibers and the coagulatingmedium out of the spinning tube, said discharge funnel increasing incross-sectional area toward the outlet end thereof whereby the velocityof the coagulating medium flowing therethrough will decrease toward theoutlet end thereof and the coagulating medium will not spurt from theoutlet end of said funnel, and an overflow from said first trough tosaid second trough for maintaining a constant head of coagulating mediumin said first trough on the inlet funnel.

References Cited in the file of this patent UNITED STATES PATENTS1,022,097 Linkmeyer Apr. 2, 1912 2,027,419 Dreyfus Jan. 14, 19362,210,826 Williams Aug. 6, 1940 2,243,116 Ostermann May 27, 19412,288,982 Waterman et al July 7, 1942 2,313,006 Ufnowski Mar. 2, 19432,447,994 Wicker Aug. 24, 1948 2,450,750 De Locotte et a1 Oct. 5, 19482,502,972 McCallum Apr. 4, 1950 2,517,711 Pool et al. Aug. 8, 19502,532,458 New Dec. 5, 1950 2,558,734 Cresswell July 3, 1951 2,559,700Bauer July 10, 1951

1. AN APPARATUS FOR THE PRODUCTION OF FILAMENTARY MATERIALS COMPRISING ATROUGH FOR HOLDING A COAGULATING MEDIUM, A SECOND TROUGH CONTIGUOUS TOSAID FIRST TROUGH, A CHANNEL COMMUNICATING WITH SAID TROUGHS FORCONDUCTING OVERFLOW COAGULATING MEDIUM FROM SAID FIRST TROUGH TO SAIDSECOND TROUGH, A SPINNING JET POSITIONED IN SAID FIRST TROUGH FOREXTRUDING A FILAMENT-FORMING COMPOSITION INTO SAID COAGULATING MEDIUM INTHE FORM OF FILAMENTARY MATERIALS, AND A GENERALLY U-SHAPTED SPINNINGTUBE EXTENDING FROM SAID FIRST TROUGH TO SAID SECOND TROUGH FOR CARRYINGTHE